How to scale multiple textures?
You might be better off here using a single image that is tileable and the unwrapping the faces from views, and scaling the UV selections in the uv image editor. You can regulate the mapping by selecting a row of faces and choosing 'follow active quads' in the unwrap options. edit: I forgot to mention that you could do this on a second uv map, and then bake to the first one once you get the scale in your preferred size - this would then allow you to paint into the result with some variations like dirt or discoloration and not be stuck on the single tiled texture.